Google can now track your offline purchases

Google runs the world's largest and most profitably online ad network, but the lion's share of ad dollars still go to TV. The search giant is looking to change that by associating online ads with purchases in the real world — your purchases. Google has partnered with companies responsible for tracking purchase data, which gives it access to about 70 percent of all US credit and debit card transactions. This all comes off as a little creepy, but Google is adamant that it's not creepy at all.

Right now, Google and other online advertisers lack the data to draw a strong connection between online ads and purchases in real life. Google has the tools to track what you buy online, assuming you remain logged into your account and choose to share your browsing data. Offline, Google can do little more than track your location to guess at what you're buying and peek at data from Android Pay. Google's hope is that offline purchase data will confirm that the ads you see online do, in fact, influence what you buy in real life. That could tempt companies to increase ad spending online, which would be a windfall for Google.

This new wealth of data from brick-and-mortar merchants will allow Google to associate your real life purchases with the ads it shows you online. For instance, if you clicked on an ad while searching for a new camera, but didn't buy anything, the advertiser would conclude the ad didn't work. However, what if you went to the advertiser's physical store and bought it? That's potentially even more valuable to the advertiser, but Google needs a way to connect those two actions.

Google says it anonymizes the data it uses to identify users in ad tracking by converting all personal information to a string of characters. Neither Google nor third-parties can connect that value to a real person. So, technically all an advertiser knows is that unique ID saw an ad online and then showed up in a store to buy something. The only difference now is that your unique ID will be popping up in real life.

If you're still getting the heebie-jeebies from this, Google does include ample privacy tools to limit what data it can collect and use. Swing by your Google Dashboard and log in with your account. You can turn off ad personalization and use your activity controls to stop Google from collecting data from searches, location, and more. Keep in mind, many Google services will be less useful if you turn these features off. Alternatively, you can simply stay logged out of Google unless you specifically need to access your account.